To caramelise onions, heat up olive oil in a frying pan, and add the sliced onions. Saute until soft and golden. Add the beer and demerara sugar, and cook until the beer dissolves. Set aside to cool. At this point prepare the challah.
Prepare a springform bundt pan or springform pan with a ball of aluminum foil in the center and spray it with cooking spray. I prefer the springform bundt pan because the center is widest and easier to fill with the hummus basar!
Sprinkle your work surface with flour.
Divide the challah dough into two. Cut each half into four pieces, and each of those into five pieces, so you have 20 small pieces(from each half of dough).
Press each piece with the palm of your hand to flatten into a disc, and fill the inside with caramelised onions.
Take the edges and bring them up to meet in the center to close the dough into a small parcel. Take half of the parcels and dip the smooth side down into a bowl of sesame seeds.
Take the 10 parcels with seeds, and place them sesame seed side-up around the center of the pan, not touching the middle piece. (the more space you have in the center, the bigger size bowl you can fit!)
Take the other 10 parcels and place them along the outer edge of the pan, each in the center of two with the sesame seeds. It might look like there’s a lot of empty space, but they will fill out when baking.
Combine egg and water for egg wash and brush rolls lightly.
Let rest for 10 minutes.
While dough is resting, prepare filling.